Level select:
Press Left, Right(2), Up at the game selection screen.

Level skip:
Pause game play and press C.

View death sequences:
Enter one of the following passwords at the "Video Mode" option.

Level	Password
70000000 B.C.	BMCFXWRL
65000000 B.C.	GJRPQVKS
3000000 B.C.	THMZCYFB
1600 B.C.	RYFGSXDK
44 B.C.	FTGBDQPW
500 A.D.	VSLCZKTJ
999 A.D.	CYVZPBMG
1588 A.D.	DRXHTLQJ
1941 A.D.	WBMRJZVH
1991 A.D.	SHKXGJWF
2001 A.D.	XPTMCSHD
2010 A.D.	ZVYFLGQJ
3001 A.D.	QWCDHRKT
3999 A.D.	PLQTVMXY
4000 A.D.	LKDWBSYF
4001 A.D.	KVGPRZCW