not an expert... but if it has "something like" a copy-righted material then you are into the area of derivative works and they fall under the original copy-rights. There are regional variations in the rules around them and there are allowed usages such as for parody, etc... however my mildly-educated laymans perspective of it is that if it's recognisable as "something like", then it's likely to be in dodgy territory.
your only argument against this is that something like pacman has become so universal and has been historically unprotected, that it is now public domain... this is not the case here.
PS: there is also the useful fact of life, suing you costs... for hobbyists they are likely only to tell you to stop using it, if they detect you, and if you are using it in a relatively harmless way - and detection is very unlikely if you have a small group of viewers or you are very small scale. However if you are confusing or damaging their brand (which happens when you get popular) or trying to leverage their brand to YOUR commercial success, they will hit you hard