These games looked different and interesting so I decided to draw closer and investigate. The first game greets you with an excellent intro screen featuring a mishmash of alien Sentai characters, a planet, spaceship, and a naked lady. The latter is an android which functions as a kind of Cortana (Halo), and she is displayed prominently at the side of the screen throughout the entire game. She actually changes appearance with upgrades and can help the party out, so she's not purely decorative.
When computers were less powerful, the playfield of some games was rather small, so pinups were naturally sprinkled around the borders. Here I'll let the eroge (erotic games) Rance 4.2 and long title provide examples for the curious. Golden Art-Nouveau swirls were also really common, as we can see in Chaos Angles.
The games play like a tile-based first person dungeon crawler RPG, though the "3D" viewport is tiny. You may convince some enemies to join your ranks once defeated. The first game had some random head/body switcharoo going on, but the second/remake seem to have used unique images for the enemies. Enemies are fought using a form of psychic/magic beam tug-of-war (like you've seen in so many movies). I don't quite understand the mechanics of it.
I drew some stuff using a ballpoint pen for a change, then I cleaned up a little with Photoshop.
Each row corresponds to a level's (map's) fauna (about 4-5 enemies each), higher levels go further down. A lot of the figures are still unrefined scribbles. The bottom stuff is more from the first game which had different enemies. The original designs were mostly humanoid, so I tried to find ways to vary the body shapes a little. It would be neat if each enemy had different frame depending on if they're winning or losing the battle, to create visual tension.