Thanks for finding the bug, Vanguard.
You're welcome.
Now that I've been able to finish the game, here's my full review:
I think that it's a fun game overall. I like how the two different ships control slightly differently. I like how messy and chaotic things look as bits of broken walls and dead worms are flying all over, and I like using gold to upgrade your ship and access new parts of the game area. It's fun (if a bit overpowered) to spam all of your bombs over an area overrun with worms.
As was said before though, the game area is too big for what the game does, and I think there were a few missed opportunities. The larger ship is mostly dead weight that has to be carried around for the smaller ship. Maybe it would be better if the big ship could auto-follow when the player wants it to, or have some sort of digging ability of its own so the player doesn't need to always make two trips. The worms make good enough enemies, but more variety would be good, like worms that can dig slowly, worms with ranged attacks, enemies that can only be dealt with using the large ship, or stronger, non-respawning enemies.
Since the only way to repair the big ship is by collecting gold, it means that damage is not particularly significant near the start of the game, where you'll level soon enough anyway, but after level 6 (is that the level cap? If it's not it may as well be, since getting to level 7 takes longer than finishing the game does) all damage to the big ship is permanent. Maybe it would work better if levelling up didn't heal you, but instead you recovered a tiny bit of health for every few pieces of gold you collected so the big ship would have a reason for collecting it after level 6. Then again, you could exploit that by waiting for a room to fill and bombing the crap out of it, so I dunno.
A few people complained about the graphics, but I think they kind of work. It feels kind of like an old Atari game to me. I already mentioned that I liked the bits of rock and enemies flying around. The repeating textures on the rocks don't make them look entirely solid or natural, but they do make it easy to tell exactly how many squares there are between any two points, and they also show "veins" of different types of rock, which is a nice little touch. I think I liked the blue ship better than the brown one, but that's okay.
Overall the game is flawed, but still good.