As far as I'm aware Fire Horse didn't start life as a land casino game, a guess that I feel more sure of when looking at the graphical quality of the game - many IGT slots suffered a graphical downgrade when they were converted for on-line use perhaps due to the limited bandwidth available from modems at the time, but that's a step that is wholly unnecessary in the age of superfast broadband. This game looks pin sharp to me and the symbols are colourful and detailed just as I would expect from an on-line game.
I always think it's an odd choice when slot creators choose to add scatter symbols which payout but with no bonus round, then another set of symbols that start the bonus round only with no payout. I guess it must be necessary to accommodate the required RTP but it can be extremely frustrating if a large number of both sets of symbols land on a single spin yet there just isn't quite enough of either to actually award anything! In Fire Horse even five of the scatter symbols pay just 50x your stake, which exacerbates the problem even more although I think the huge maximum of 96 free spins just about makes up for it on a lucky day!
With the 1440 effective pay ways it's not surprising to find the wins listed in the paytable seem quite low but the stacked wilds on reels 2, 3 and 4 make it possible to win on a huge number of these ways on a single spin and therefore huge wins are still possible. I've seen a few hits over 1000x stake on Siberian Storm and I've no doubt this game is capable of hitting just as big. IGT games don't really get much better than this!