For such a short 2D metroidvania game, the developers really knew how to pack in a nice difficulty curve, platforming, and surprisingly non-standard tech into this game!
CaveBuster might seem like your standard metroidvania (shoot, platform, gain upgrades), but it's beauty lies in the fact that it's both well-crafted, punishing, and employs the use of something that has always been a form of cheese for me: damage boosting. The controls feel really well put together, and the graphics are very reminiscent of something you'd find on a handheld console. While the ability to use your laser and double jump is received later in the game, the developers made sure that each section felt like the progression was required and didn't fall into the issue of upgrades being useless. I know I've mentioned this before, but the fact that there are sections in the game that require damage boosting to progress is amazing; damage boosting is typically reserved in platformers as a means of cheesing through areas by either using i-frames to bypass enemies or to gain extra height in unintended ways, so the fact that this game has that as an actual tech that's required to progress speaks volumes of the developer's knowledge on these types of games.
All in all, this is a by-the-book, short metroidvania game that ticks all the right boxes and gives veterans of the genre a nice smile and nod. Runtime is about 10 minutes, so I'd highly recommend checking this out :)
My playthrough: