diff --git a/src/filter.js b/src/filter.js
index 397dfd3..ca091b6 100644
--- a/src/filter.js
+++ b/src/filter.js
@@ -9,9 +9,8 @@ const _false = () => false
 const _and = arr => p => arr.map(e => e(p)).reduce((a, b) => a && b)
 const _or = arr => p => arr.map(e => e(p)).reduce((a, b) => a || b)
 
-const similar = (key, reference, name, units) => {
+const similar = (keys, reference, name, units) => {
     let neg = false
-
     if (reference.startsWith('-')) {
         neg = true
         reference = reference.slice(1)
@@ -20,15 +19,19 @@ const similar = (key, reference, name, units) => {
     // support both string or regex as reference
     let internal_tester = val => (''+val) == reference
     if (reference.startsWith('/')) {
-        const regex_parts = reference.split('/')
-        regex_parts.shift() // remove starting slash
-        const flags = regex_parts.pop()
-        const regex = new RegExp(regex_parts.join('/'), flags)
-        internal_tester = val => regex.test(''+val)
+        try {
+            const regex_parts = reference.split('/')
+            regex_parts.shift() // remove starting slash
+            const flags = regex_parts.pop()
+            const regex = new RegExp(regex_parts.join('/'), flags)
+            internal_tester = val => regex.test(''+val)
+        } catch (ex) {
+            throw new Error(`Invalid regex "${reference}" found at filter "${name}"!`)
+        }
     }
 
     // support strings, arrays, or objects as key
-    const external_tester = point => {
+    const external_tester = (point, key) => {
         const value = u.deep(point, key)
         if (a.type(value)() == 'array') {
             return value.some(subkey => internal_tester(subkey))
@@ -39,11 +42,12 @@ const similar = (key, reference, name, units) => {
         }
     }
 
-    // negation happens at the end
+    // consider negation
     if (neg) {
-        return point => !external_tester(point)
+        return point => keys.every(key => !external_tester(point, key))
+    } else {
+        return point => keys.some(key => external_tester(point, key))
     }
-    return external_tester
 }
 
 const comparators = {
@@ -75,7 +79,7 @@ const simple = (exp, name, units) => {
         value = exp
     }
 
-    return point => keys.some(key => comparators[op](key, value, name, units)(point))
+    return point => comparators[op](keys, value, name, units)(point)
 }
 
 const complex = (config, name, units, aggregator=_or) => {
@@ -109,7 +113,7 @@ const contains_object = (val) => {
 }
 
 exports.parse = (config, name, points={}, units={}, asym='source') => {
-    
+
     let result = []
 
     // if a filter decl is undefined, it's just the default point at [0, 0]
diff --git a/test/unit/filter.js b/test/unit/filter.js
index c040687..3972e93 100644
--- a/test/unit/filter.js
+++ b/test/unit/filter.js
@@ -49,17 +49,21 @@ describe('Filter', function() {
         names(filter('/^o/', '', points)).should.deep.equal(['one', 'three', 'mirror_one'])
         // middle spec, should be the same as above, only explicit
         names(filter('~ /^o/', '', points)).should.deep.equal(['one', 'three', 'mirror_one'])
-        // full spec (n would normally match both one and even, but on the tags level, it's just even)
+        // full spec (/n/ would normally match both "one" and "even", but on the tags level, it's just even)
         names(filter('meta.tags ~ /n/', '', points)).should.deep.equal(['two'])
+        names(filter('meta.name,meta.tags ~ /n/', '', points)).should.deep.equal(['one', 'two', 'mirror_one'])
         // negation
         names(filter('meta.tags ~ -/n/', '', points)).should.deep.equal(['one', 'three', 'mirror_one'])
+        names(filter('meta.name,meta.tags ~ -/n/', '', points)).should.deep.equal(['three'])
         // arrays OR by default at odd levels (including top level)...
         names(filter(['one', 'two'], '', points)).should.deep.equal(['one', 'two'])
         // ...and AND at even levels
         names(filter([['even', 'prime']], '', points)).should.deep.equal(['two'])
         // arbitrary nesting should be possible
         names(filter([[['even', 'odd'], 'prime']], '', points)).should.deep.equal(['two', 'three'])
-        // anything other than string/array/object/undefined is an error
+        // invalid regexes should throw meaningful errors
+        filter.bind(this, '/\\/', '', points).should.throw('Invalid regex')
+        // anything other than string/array/object/undefined is also an error
         filter.bind(this, 28, '', points).should.throw('Unexpected type')
     })