I really like the Gauntlet! I was planning out teams before the site even went down for pre-launch maintenance and love seeing my team work well. My first goal when the game fully launched was to get my team set up an running, and I play it several times a day.
Something I've found though is that my team can be doing absolutely brilliantly one round, and then get totally demolished the next with no warning. I suppose that's the risk you run with the gauntlet currently, but it leaves me feeling like every round is a coin flip whether I come up against a good team or not. It leaves me feeling out of control in a game where planning and judging your capabilities are key, and if you make one bad decision the whole run is bust.
I would like to suggest that the player is shown silhouettes of the enemies they will face next round when they complete a round. This will let the player decide if they think the next round will be worth the risk - if they know what the silhouettes are! This would encourage the player to familiarize themselves with what enemies can appear, and even what synergy the team may have. It's a mechanic that helps out the more you play the gauntlet, and will even help you learn your team's weaknesses and strengths. Having the silhouettes doesn't guarantee a win either if the odds are close, so there's still a risk!
I think this would be a good update to the Gauntlet, and would encourage players who felt they were blindsided by a difficulty increase to have another go.
