There's no full screen/windowed toggle, so I've not been able to take any screen captures. The ones included below were from the internet. I couldn't find a video online either. If I have time (unlikely) I try and make a short video of game play this evening)

Caveman Rudi vs. Big Feet:

In Brief:
A 14 level, room based, easy, 2D platformer, with a colourful graphic and pseudo 3D feel.

The Game:
Control Rudi using the Arrow keys. He's on a search for fire after his enemy Big Feet has frozen his homeland.

Use stones to kill enemies; these are are not limitless, so you'll need to pick up more as you progress, (some as piles of stones, others that drop from above). You can also return to previous levels to pick up more stones if required (falling stones will still be falling in those previous levels). Some platforms require you to climb icicles to get to the higher platforms.

Use Rudi's club (that you have to pick up on the second level) to unblock exits to new levels, but only once you've collected all of the crystals on that level. Use the stones you've picked up to dispatch any enemies you encounter by using the ctrl key. Enemies include Zombies, Werewolves, Vampires and large spiders as well as other enemies such as Ice monsters, Big Feet and Carnivorous Plants. Some of these may respawn after a short time so be sure to find everything of value as quickly as possible (though there's no time limit) on the level before progressing to the next level. The plants tend to guard piles of stones. Spiders are not introduced until later in the game. They crawl down icicles that you also use to climb to higher places; so, you'll need to destroy them before using the icicle.

Collect all the crystals and food on each level to score points. When you kill an ice monster they leave a health boost for you (in the form of a group of hearts). Some levels require a key to progress further. There are three indicators at the corners of the game screen. The top left indicates your score, the bottom left indicates your health and the bottom right the number of stone you have left to throw. Watch out for various obstacles like falling icicles and steam vents that will take away some of your health if you get hit or caught in one or if you fall into a pit. Some enemies also throw projectiles at you. At one point you can pick up a temporary invisibility shield that will protect you from Big Feet.

The game is divided into levels, the first one being a practice level to allow you to get used to the controls with no enemies to stop you. As you progress in the story mode you'll see a storyboard with advice, introducing each level. Around Level 6 you have to destroy ice monsters using a catapult; use your mouse pointer to direct the ammunition onto the ice monsters and the left mouse button to fire them. Later, once you've unlocked all fourteen levels you'll unlock an endless mode as well as the ability to upgrade spells that come into force later in the game.

Controls:
Left and Right arrow keys = Move Left or Right
Up and Down arrow keys = Climb Up or Down ladders
Up Arrow = Jump
Down Arrow = Crouch
Ctrl = throw stones or spells
Space = Hit with a Club
Esc = Back to Menu or Pause
LMB = Use the Catapult
Mouse Pointer = Aim at Ice Monsters

Conclusion:
Overall Caveman Rudi vs. Big Feet is a nice little platformer that's not too challenging; which for me is ideal. It's definitely one worth downloading :) The only negative I would say about this game is that progress is not saved during the story mode until you've completed all fourteen levels and unlocked the endless mode.

The game has overtones of Nintendo Switch's remake of the 1991 SNES/Amiga Genesis/DOS game Joe & Mac: Caveman Ninja. You can get the original DOS version of the game for free HERE; you'll need to use DOSBox to run it though. There's a tutorial over in the game discussion sticky section how to use DOSBox in conjunction with an early version of Norton Commander HERE.

Notes on Security
Scanning the installed game with the free version of Virus Total, it scored two hits. These were the ones that are commonly associated with most free game sites, i.e. Jiangmin & VBA32; (they indicate suspected trojan downloaders or adware). There were 61 other antimalware suites that gave the game a clean bill of health, so it's almost 'certain' that todays game is free of any issues and the results are false positives. You can see the scan HERE

I've included download links to a few sandbox programs attached to this comment below for anyone who is not happy to install the game without checking first to see if the game is safe. 'All' free game sites include low level adware that is completely isolated to the game and does not inject any spurious code into your computers system. The aim of the low level adware is to earn the distributor and developer some money in recompense for allowing the game to be given away.