Gain Ground (SEGA Genesis)

Level Select Options screen: press ACBC.

EASY mode doesn't have ROUND 4.

There are 5 ROUNDS.

Rescue Everyone You have to actually bring hostages to EXIT to get them enrolled in your army, beating the level doesn't automatically pick them up.

I played my first good game of this, reaching ROUND 3, I think I understand it a bit better. I think you beat levels by either killing every enemy or moving all your troops from the starting point to the EXIT. If you pick up hostages, they will join your army.

The FAQ by Jungon states that you can replay levels to stock up on troops.

My current understanding of this game is that it has 3 vertical levels: ground, elevated, and rooftops (e.g. ROUND 2 STAGE 3). The standard attacks are on the ground level, grenades and reach the elevated level, and the viking can reach all 3 levels.

I reached ROUND 4 (which is modern times, i.e. 1980s) level 9 and lost too many dudes to continue. When you game over, continuing is pointless, because your army doesn't have the required abilities.