Sorry for my inactivity. I was at the point in my cab's construction where I could get it functional if I just put in a good week's worth of work. Definitely worth it. I have come back to figit around with this game though, pretty fun.
I played around a bit and noticed pretty quickly the way to get the most points per level is to blow up all enemies at the same time to get the multiplier. Getting the highest multiplier is actually a pretty big deal in terms of point difference. And when enemies are spread out you can still get that multiplier with the bombs you have to manually explode.
I've gotten really good at the first 3 stages so I'll post my quick strategy on each of those. Next stages will come later when I figure them out.
1: Pretty easy. Grab all the powerups on your starting side then blast your way to the other side without killing any of the enemies. Take the powerups over there then you should be able to easily set a bomb in the enemy alley with enough blast range to get them all at once. I have 2100pts after stage 1.
2: A little more tricky, need to figure out the layout. There are 4 range upgrades and a manual detonation upgrade that can all be obtained without opening any paths to enemies, grab them first. Next, there are two bomb capacity upgrades in the bottom left. Get those two as the enemy is walking away from you then quickly dart to the top right to blast out the bomb located up there and grab it. Now you should be able to drop 4 manual detonation bombs. Now, try your best to not attract the enemies out of there path in each corner, you want to isolate them. Block each of the enemies in their respective 4 corners with bombs then move to a safe place and quickly blow them all at the same time. I usually have 12600pts after this stage. However, if you get lucky you can trap them in a way where the higher point enemies get the highest multiplier. Most I got after this stage is 13300.
3: You can blast away a lot of blocks without opening any paths to enemies, do so now to get the upgrades. There will be lots of bomb range and capacity upgrades and at least one (maybe two?) manual detonation upgrades. Now is a tricky part, refer to 0002.png attachment for placement. Place each bomb in the location specified in that specific order. There are two match icons (one in top left area and other in bottom right area) that give 5000pts each. Obviously we need to get those. The exact moment the enemies start to hide, blast each bomb in series, NOT all at once, you want bomb 1 and 2 to clear a path first so bomb 3 and 4 can follow up and blast the two blocks that have the 5000pt matches. Immediately pick up these matches while the enemies are hidden. Also, as you're grabbing them, begin placing bombs in spots that will blast one or two enemies when they resurface. With a little practice you should be able to quickly detonate all bombs at once and kill all enemies. Most points I had after stage 3 was 31700.
Then I just kinda freestyled to get the rest of my points. Once I get a good handle on the later stages I'll update if requested. Hope this helps!
0003.png attachment is my highest score so far.