Note that both have been played and completed as single player for this match up.
Gauntlet: Slayer Edition
Straight up Gauntlet still wins in dungeon design, graphics, and number of foes in a zone. The Slayer Edition adds a load out screen that you can spend your hard earned gold on to buy cosmetics or upgrade weaponry, as well as a nifty map which doubles as a level selector. Maps are mostly three types: Get from point A to B, Survive Waves of Monsters, or kill a boss - of which there are three.
I wish they explained why this guy is blue though.
Reviving requires use of a Skull Coin which you earn by slaying enough monsters per level - and once you finish the story you can also try "endless" mode as well as the weekly tournaments to gain earn new cosmetic capes.
Forced: Slightly Better Edition
The main thing the upgrade fixes for me is it now saves your progress, which is pretty important! Forced easily wins in the story, puzzle and character customization/development departments. Each of the four classes can choose 3 active and 3 passive skills from a list of 10 in each - which you unlock by completing various trials and challenges. You can earn 3 skill points (once) per trial through completion, completion within a set time, and completion while doing an extra challenge - such as not healing or reaching some bonus objective.
The time and extra challenges are often weighed against each other too, meaning if you want -full- completion you will need to play the challenges more than once, in a different way which adds replayability. Dying forfeits your attempts for said challenges on a run and 3 deaths is game over.
The clever mechanic of the spirit ball is what really gets you thinking though, as your mastery on controlling it while fighting off enemies is vital, especially if you wanted to complete said challenges. Speaking of enemies, I do appreciate that each foe here is unique in their behavior, unlike the glut in Gauntlet where minions per level basically behave the same, they just run faster and have more HP the deeper you get. In Forced, you see an axe guy you dodge him a particular way as opposed to a sword guy.
It's also a test of how much you can keep track of at once!
Forced also has five bosses, and after beating each boss a smaller, minion type of them begins to appear in further trials. Again good design as the player would have learned their move set by then.
My Result: After that review it shouldn't be a surprise that Forced wins this match, due to the game variety mechanics, customization, and game length. Especially if you are going to play as a solo player, Forced will now give you more bang for your buck. What can I say? Against Gauntlet, it's just slightly better.