This is the Sega Master System port of Wonderboy in Monsterland. Originally an arcade game, it was ported to the SMS and the PC Engine/TG16, as well as some home PC's like the Amiga and C64. The PC Engine version was reskinned into a Bikkuriman game(but is very close to the arcade version), and Jaleco ported and reskinned it into Saiyūki World for the Famicom, which was popular enough that the sequel got brought to the US as Whomp'em.
You are on a constant time limit, every time the hourglass flips you lose 1 heart of health. This fucks you worse than you think, since the amount of maximum health you have is tied to your points. You need about 400K to have 10 hearts. The most points you can get is through getting to the end of the level with maximum health. Not only are you getting punished for taking damage from enemies, you are also getting punished for not rushing through. Oh, and there is no way to continue. You die, you better hope you have the revival potion or it's game over.
Your attack hitbox is a tiny little bit in front of you. Some bosses have homing attacks that you just can not dodge. There's a hidden subquest that you really NEED to do to have a reasonable chance of either reaching or beating the final boss, and every door involved in the quest is invisible and only the first one gets pointed out to you. Gold is RNG based, so you never know if you'll have enough money for the upgrades you really need. Not knowing how the shops work and buying the wrong upgrades can make it impossible to get the best equipment in the game. There's an entire level that can be missed if you don't take a certain path.
All that being said, it's a very fun platforming-action/rpgish game. This port is also much easier than the arcade version in terms of bosses. Once you get past the learning curve and stop running into enemies you meant to attack, it's pretty fun. The only part of the game I really didn't like was the final level. Let me tell you about the final level.
The final level is a maze filled with high level enemies everywhere. If you have the Bell item from the hidden subquest, it will let you know when you are taking the right turn. Otherwise, if you have the Ruby or you didn't complete the subquest, you have to know the route. Taking a wrong turn can dump you in any number of locations, or even back at the very start of the level. 2/3rds of the way through is a section where you have to make very carefully timed jumps back and forth between two moving blocks. You have to do this straight up for about 3-4 screens. One mistake, and you fall. If you fall, it dumps you at the bottom of a DIFFERENT tunnel, and you will have a bit of a walk to get back to where you were to try it again. Keep in mind the timer, and you will realize just how much of a dick move this is. The last level is the only level without any shops, so no more equipment improvements, or health refills are possible. And provided you get past that bullshit, you get to fight the final boss. If you have the Ruby, it will take away half the boss's health. If not, it will be a long battle even with the best sword in the game, which you will only have if you found the hidden sword upgrade. Hopefully you also have the revive potion, since once you beat the boss he comes back to life at full health and moves and attacks much quicker. And your reward for winning is a single screen of engrish plot. Hooray.
It's a pretty fun game, but one I usually stop playing around the last level.