The Robins lie seventh in League Two after Saturday's 1-0 win at Bury, but Allen is far from satisfied.
He said: "I am pleased with the way the team has settled in, but I wouldn't say I am happy because we have a lot more to do.
"We have to keep developing and improving and stay hungry to retain the passion and desire to progress as a team.
"I have given them a little pat on the back, but there is so much work to do. They are all aware of it and they have all been told they can do better."