A note from Stop

A custom challenge spawnset with spawns that end at 1200s - 20 minutes.
No loop. Definitely possible.
Difficulty generally increases with time survived.
4 difficulty tiers are unlocked through time survived:
{ 0-287s ~ 288-665s ~ 666-999s ~ 1000-1200s }
At 0, 287, 666 and 1076s Leviathans will spawn - 4 in total but all are arguably slightly easier (just different to) V3.
Start radius
End radius
Shrinking rate
Brightness
90
66.7
0.0247
133
Seconds
Spawns
Gems (no farm)
Total gems
0.0000
Leviathan
6
6
0.0000
Gigapede
50
56
22.0000
Gigapede
50
106
41.5000
Gigapede
50
156
60.2500
Gigapede
50
206
77.7500
Gigapede
50
256
94.0000
Gigapede
50
306
110.1250
Centipede
25
331
110.2361
Squid I
2
333
126.2361
Centipede
25
358
126.3472
Squid I
2
360
126.5694
Squid II
3
363
142.5555
Squid I
2
365
142.6666
Squid I
2
367
142.8888
Squid II
3
370
158.7499
Squid I
2
372
158.9721
Squid II
3
375
159.4165
Squid III
3
378
180.0415
Gigapede
50
428
195.3415
Gigapede
50
478
195.3415
Squid I
2
480
195.3415
Thorn
0
480
210.4415
Gigapede
50
530
225.2415
Gigapede
50
580
225.2415
Squid II
3
583
225.2415
Thorn
0
583
225.2415
Thorn
0
583
239.6415
Gigapede
50
633
253.7415
Gigapede
50
683
253.7415
Squid III
3
686
253.7415
Thorn
0
686
253.7415
Thorn
0
686
253.7415
Thorn
0
686
267.6415
Centipede
25
711
287.6415
Leviathan
6
717
287.8637
Squid I
2
719
288.0859
Squid I
2
721
288.5303
Squid II
3
724
289.4191
Squid III
3
727
307.0000
Squid II
3
730
323.0000
Squid I
2
732
336.7191
Spider I
1
733
336.7191
Spider II
1
734
336.7191
Squid II
3
737
337.7191
Spider I
1
738
337.7191
Squid III
3
741
338.7191
Spider I
1
742
339.7191
Spider I
1
743
340.7191
Spider I
1
744
341.7191
Spider I
1
745
370.2191
Gigapede
50
795
383.5191
Gigapede
50
845
396.6191
Gigapede
50
895
409.5191
Centipede
25
920
409.8524
Squid I
2
922
422.5524
Centipede
25
947
422.8857
Squid I
2
949
423.5523
Squid II
3
952
436.0523
Centipede
25
977
436.3856
Squid I
2
979
437.0522
Squid II
3
982
437.7188
Squid II
3
985
450.0188
Centipede
25
1010
450.3521
Squid I
2
1012
451.0187
Squid II
3
1015
452.3520
Squid III
3
1018
464.4520
Centipede
25
1043
464.7853
Squid I
2
1045
465.1186
Squid I
2
1047
465.7852
Squid II
3
1050
466.4518
Squid II
3
1053
467.7851
Squid III
3
1056
485.7851
Squid I
2
1058
485.7851
Squid I
2
1060
485.7851
Squid I
2
1062
485.7851
Squid I
2
1064
485.7851
Squid I
2
1066
495.1351
Ghostpede
10
1076
495.1351
Squid II
3
1079
495.1351
Squid II
3
1082
495.1351
Squid II
3
1085
522.4851
Gigapede
50
1135
522.4851
Squid III
3
1138
522.4851
Squid III
3
1141
545.0851
Spider I
1
1142
545.0851
Squid I
2
1144
545.0851
Squid II
3
1147
556.1851
Spider II
1
1148
556.1851
Squid III
3
1151
556.1851
Thorn
0
1151
556.1851
Thorn
0
1151
556.1851
Thorn
0
1151
566.8851
Ghostpede
10
1161
566.8851
Ghostpede
10
1171
577.3851
Spider I
1
1172
577.3851
Squid I
2
1174
580.0517
Squid III
3
1177
589.9517
Gigapede
50
1227
593.2850
Squid I
2
1229
594.6183
Squid I
2
1231
595.9516
Squid I
2
1233
600.9515
Squid I
2
1235
602.6181
Squid I
2
1237
604.2847
Squid I
2
1239
610.9513
Squid II
3
1242
614.2846
Squid II
3
1245
620.9512
Squid III
3
1248
620.9512
Centipede
25
1273
630.9512
Gigapede
50
1323
638.8846
Centipede
25
1348
666.0000
Leviathan
6
1354
681.0000
Squid I
2
1356
687.0000
Squid I
2
1358
693.0000
Squid II
3
1361
693.0000
Squid II
3
1364
710.9846
Squid III
3
1367
728.4290
Spider II
1
1368
733.9290
Gigapede
50
1418
733.9290
Spider I
1
1419
740.0290
Squid I
2
1421
743.6956
Squid I
2
1423
747.3622
Squid I
2
1425
754.6955
Squid II
3
1428
754.6955
Spider I
1
1429
762.0288
Squid II
3
1432
762.0288
Spider I
1
1433
769.3621
Squid II
3
1436
781.5287
Squid III
3
1439
800.5287
Gigapede
50
1489
800.5287
Gigapede
50
1539
800.5287
Thorn
0
1539
800.5287
Thorn
0
1539
800.5287
Thorn
0
1539
819.5287
Spider II
1
1540
819.5287
Thorn
0
1540
819.5287
Thorn
0
1540
819.5287
Thorn
0
1540
824.7287
Spider I
1
1541
831.1287
Spider II
1
1542
838.9287
Gigapede
50
1592
848.7287
Spider I
1
1593
855.3887
Squid I
2
1595
868.9887
Thorn
0
1595
868.9887
Thorn
0
1595
868.9887
Squid III
3
1598
868.9887
Squid II
3
1601
868.9887
Squid II
3
1604
882.5887
Thorn
0
1604
882.5887
Thorn
0
1604
882.5887
Thorn
0
1604
882.5887
Squid III
3
1607
882.5887
Squid II
3
1610
882.5887
Squid II
3
1613
896.1887
Thorn
0
1613
896.1887
Squid III
3
1616
896.1887
Squid II
3
1619
909.7887
Thorn
0
1619
909.7887
Squid I
2
1621
909.7887
Squid I
2
1623
909.7887
Squid I
2
1625
909.7887
Squid I
2
1627
909.7887
Squid I
2
1629
909.7887
Squid I
2
1631
909.7887
Squid I
2
1633
909.7887
Squid I
2
1635
909.7887
Squid I
2
1637
923.3887
Squid II
3
1640
936.9887
Thorn
0
1640
937.9886
Squid I
2
1642
938.8219
Squid I
2
1644
940.4885
Squid II
3
1647
941.2001
Squid II
3
1650
941.2001
Squid III
3
1653
954.2001
Ghostpede
10
1663
967.2001
Gigapede
50
1713
967.2001
Centipede
25
1738
997.0000
Thorn
0
1738
997.0000
Thorn
0
1738
997.0000
Thorn
0
1738
1000.0000
Squid III
3
1741
1000.0000
Spider I
1
1742
1000.4500
Spider I
1
1743
1000.7400
Spider I
1
1744
1002.0400
Spider II
1
1745
1002.6400
Squid II
3
1748
1004.8400
Squid I
2
1750
1004.8400
Squid I
2
1752
1004.8400
Squid I
2
1754
1006.5400
Squid III
3
1757
1010.9400
Squid II
3
1760
1013.0500
Squid II
3
1763
1014.3000
Squid II
3
1766
1014.4000
Gigapede
50
1816
1014.5000
Centipede
25
1841
1015.7333
Squid I
2
1843
1017.5666
Squid II
3
1846
1020.0000
Squid III
3
1849
1033.5832
Centipede
25
1874
1040.0832
Gigapede
50
1924
1076.7333
Leviathan
6
1930
1091.7333
Squid I
2
1932
1091.7333
Squid I
2
1934
1091.7333
Squid I
2
1936
1091.7333
Squid III
3
1939
1101.7333
Squid II
3
1942
1101.7333
Squid II
3
1945
1101.7333
Squid II
3
1948
1117.4833
Squid II
3
1951
1128.9533
Squid III
3
1954
1135.9533
Spider I
1
1955
1140.9533
Spider I
1
1956
1155.8088
Squid III
3
1959
1159.1421
Thorn
0
1959
1163.4754
Spider I
1
1960
1166.8087
Squid II
3
1963
1166.8087
Spider I
1
1964
1169.0309
Squid II
3
1967
1169.0309
Spider I
1
1968
1172.3642
Squid II
3
1971
1178.5000
Ghostpede
10
1981
1181.8333
Squid I
2
1983
1186.3092
Squid I
2
1985
1186.6425
Squid II
3
1988
1186.6425
Squid II
3
1991
1186.6425
Squid I
2
1993
1187.3092
Squid III
3
1996
1187.3092
Squid I
2
1998
1187.3092
Squid I
2
2000
1187.3092
Squid I
2
2002
1193.1581
Gigapede
50
2052
1198.6581
Gigapede
50
2102
1198.9914
Thorn
0
2102
1198.9914
Spider I
1
2103
1198.9914
Squid I
2
2105
1199.3247
Thorn
0
2105
1199.3247
Spider I
1
2106
1199.3247
Squid I
2
2108
1199.6581
Thorn
0
2108
1199.6581
Squid I
2
2110
1199.6581
Spider I
1
2111
1199.9081
Squid II
3
2114
1199.9081
Squid I
2
2116
1200.0000
Squid III
3
2119
1200.0000
Squid I
2
2121
1200.0000
Squid I
2
2123
End of spawnset